Basic Group of sunscreen ingredients

Note
UVB range from 290-320 nanometer
UVA range from 320-400 nanometer

The SPF rating was developed to measure the ability of a sunscreen to block UVB radiation. But we all know that UVA can cause skin damage as well. We have great sunscreen, yes, we have. Not all sunscreens are created equal, however. Some sunscreens protect against only one type of ultraviolet radiation; ultraviolet-B (UV-B). Others protect against both types of ultraviolet radiation but not entire range of UVA. Some sunscreens provide coverage for complete range of UVB and UVA. We just need to know how to pick the perfect one for ourselves.

I know it is hard and we want to trust the label, but from my own experience I've seen many products that claim 'broad-spectrum' when they offer partial UVA protection instead of full range. Each country has its own rule and regulation, which can be confusing than informative. So want simple solution? Learn to read the active ingredient list, because it is the only constant thing. Every bottle has to have an active ingredient list. Easy and simple, right? YES, it's that simple. Just check the active ingredient list and check the amount of coverage they provide. It really is that simple.

please sign my guest book

Listed below are the main sunscreen ingredients allowed in sunscreen products in sunscreen products.

• Chemical used in sunscreen to absorb UVB radiation.
• Chemical used in sunscreen to absorb UVA radiation.
• Physical UV blocker

Chemical used in sunscreen to absorb UVB radiation.(top)


PABA
Para aminobenzoic acid (PABA) and its derivatives have been used in sunscreen preparations since the 1950's. It provides effective protection in the range of 260-313 nm. Although PABA is quite effective at filtering out harmful UV rays, several of its characteristics have earned it a negative reputation among both manufacturers and consumers. First, its molecular structure makes it prone to oxidation and discoloration in products. Second, it can revert to a crystalline form and therefore be difficult to use in some types of products. It requires an alcoholic base, and can stain cloth. Finally, PABA has adverse side effect. The safety and irritancy concerns have caused many manufacturers to find alternatives such as PABA/glycerine combinations or completely PABA-free UV filters.

Advantages - Binds readily to cells in the epidermis making it fairly water resistant
Disadvantages - Causes allergic reactions and stains clothing

PABA Esters
The PABA esters are padimate O, padimate A, and glyceryl aminobenzoate. These compounds are chemically similar to PABA and provide effective protection in the range of 260-315 nm. The use of these formulations has declined with the popularity of the "PABA-free" claim.

Advantages - Fairly water resistant and do not stain clothing
Disadvantages - Cause allergic reactions

Cinnamates (top)
Cinnamates such as benzyl and octyl methylcinnamate have molecular structures that absorb UV light from 290 to 320 nm. Octymethylcinnamate is insoluable in water and is commonly found in waterproof sunscreen products. Octyl methoxycinnamate is less potent than padimate O. Diethanolamine methoxycinnamate is a water-soluble cinnamate derivative.

Advantages - Stable in the presence of sunlight and are water resistant
Disadvantages - Cause allergic reactions

Salicylates
The salicylates are homomenthyl salicylate, octyl salicylate, and triethanolamine salicylate. Salicylates have been used for a long time, even before PABA, and provide effective protection in the range of 290-315 nm. Salicylates are weak UV-B absorbers, and they are generally used in combination with other UV filters to boost the SPF.

Advantages - Stable in the presence of sunlight and are water resistant
Disadvantages - Octyl and triethanolamine salicylate can cause skin irritation

Octocrylene (top)
Octocrylene may be used in combination with other UV absorbers to achieve higher SPF formulas. Octocrylene used in combination with other sunscreen ingredients, such as avobenzone, may add to the overall stability of these ingredients in a specific formula. Octocrylene provides effective protection in the range of 250-360 nm. It is an oil soluble ingredient.

Advantages - Stable in the presence of sunlight and normally use as stabilizer for avobenzone
Disadvantages - oil soluble and can be quite heavy when use

Phenylbenzimidazole sulfonic acid
Most chemical sunscreen ingredients are oils that are soluble in the oil phase of emulsion systems, accounting, in part, for the heavy, greasy aesthetics of many of these products. Phenylbenzimidazole sulfonic acid is water soluble, and it is used in products formulated to feel lighter and less oily, such as daily use cosmetic moisturizers. It provides 290-340 nm protection.

Advantages - light weight than other chemical absorber.

Chemical used in sunscreen to absorb UVA radiation.

Benzophenones (top)
Benzophenones are unique molecules that occur as solids that absorb high levels of UV light ( 290-350nm). However, as solids, they can be difficult to successfully incorporate into products. Although benzophenones are primarily UV-B absorbers, oxybenzone absorbs well through UV-A II. Oxybenzone can be considered a broad-spectrum absorber. It significantly augments UV-B protection when used in a given formula.

Advantages - provide partial UVA protection
Disadvantages - difficult to incorporate into products

Avobenzone
Often referred to by its trade name, Parsol 1789, butyl methoxydibenzoylmethane or avobenzone provides superior protection through a large portion of the UV-A range, including UV-A I. It has been widely used in Europe for the last decade. The FDA recently approved avobenzone for use in the United States. Potentially a significant addition to sunscreen products for true broad-spectrum UV protection, concerns have been raised regarding its photostability and its potential to degrade other sunscreen ingredients in products in which it is used.

Advantages - Absorb entire range of UVA from 320-400 nanometer
Disadvantages - not stable and can degrade other sunscreen ingredient in products; requires either Octocrylene or 4-Methylbenzylidene camphor as stabilizer; can cause allergic reaction

Physical UV blocker (top)
Rather than absorbing UV rays, these compounds reflect them. Titanium dioxide and zinc oxide are the best known of this group. Because they prevent UV rays from ever reaching the skin, these physical UV blockers offer the most effective protection. With they original form, titanium dioxide and zinc oxide both provide coverage upto 700 nm. However, they also leave behind an opaque white film. (think life guard's white nose)
New technological advances have led to the development of UV blockers made of particles so small that the human eye does not perceive them and yet they still reflect UV light. Micronized forms of titanium dioxide and zinc oxide do not block the entire range of ultraviolet radiation up to 700 nm. Micronized zinc oxide has a wider UV spectrum than micronized titanium dioxide. Depending on the manufacturer, micronized zinc oxide can absorb UV-A radiation up to 380 nm or 400 nm. Likewise, the UV absorption of micronized or microfine titanium dioxide extends to 350 nm or 370 nm depending on the manufacturer.

Advantages - provide protection for both UVB and UVA (complete broad-spectrum sunscreen) Great for people with sensitive skin because their particles are too be to absorb into skin, very unlikely to cause allergic reaction.Safe for children
Disadvantages - the original form of physical blocker can leave white cast on your skin

please sign my guest book

Reference:

Active ingredients in sunscreen. http://www.wholefoods.com/products/sunscreens.html

Australian regulatory guidelines for OTC medicines (July 2003). Therapeutic Goods Administration, Commonwealth Department of Health and Ageing

Bissonnette, R. (1997) Update on sunscreen. Skin Therapy Letter,2 (5) http://www.derm.ubc.ca/skintherapy/stl0205.html

Department of Health and Human Services (1999). Sunscreen Drug Products For Over-The-Counter Human Use; Final
Monograph, Food and Drug Administration Federal Register May 21, 1999 (Volume 64, Number 98).

Fewell, H. Chemical uses in sunscreen to absorb UVB radiation. http://dermatology.about.com/cs/skincancers/a/uvbabsorb.htm

Levy, S. (2002). Sunscreen and photo-protection. http://www.emedicine.com/derm/topic510.htm

Reisch, M. (2002). Sunscreen: Active ingredients prevent skin damage. Science & Technology 80(25), p.38.

Solumedia & Barcon, D. (2000). Sunscreens 2000 -- What You Need To Know. http://www.solumedia.com/sunscreen3.htm

Thompson, L. (2000). Try to look SUNsational? Complexity persists in using sunscreen. USFDA consumers report July-August 2000